1. Field of the Invention
The present invention relates to material processing and more particularly to a method for fault detection for material process system.
2. Description of Related Art
One area of material processing in the semiconductor industry which presents formidable challenges is, for example, the manufacture of integrated circuits (ICs). Demands for increasing the speed of ICs in general, and memory devices in particular, force semiconductor manufacturers to make devices smaller and smaller on the wafer surface. And conversely, while shrinking device sizes on the substrate is incurred, the number of devices fabricated on a single substrate is dramatically increased with further expansion of the substrate diameter (or processing real estate) from 200 mm to 300 mm and greater. Both the reduction in feature size, which places greater emphasis on critical dimensions (CD), and the increase of substrate size lead to even greater requirements on material processing uniformity to maximize the yield of superior devices.
Typically, during materials processing, one method to facilitate the addition and removal of material films when fabricating composite material structures includes, for example, the use of plasma. For example, in semiconductor processing, a (dry) plasma etch process is utilized to remove or etch material along fine lines or within vias or contacts patterned on a silicon substrate.
During, for example, material processing in IC fabrication, shrinking critical feature sizes, increasing substrate sizes and escalating numbers and complexities of processes lead to the necessity to control the material processing uniformity throughout the lifetime of a process and from process-to-process. The lack of uniformity in simply one process measurable generally requires the sacrifice of other important process parameters, at least, somewhere during the process. In material processing, the lack of process uniformity can, for example, cause a costly reduction in the yield of superior devices.
Attempts to design material processing hardware either to produce uniform processing properties or correct for known non-uniformities are further complicated by the expansive set of independent parameters, the complexity of these material processing devices, and simply the exorbitant cost and lack of robustness of such material processing devices. Furthermore, for conventional material processing devices, the number of externally, controllable parameters are severely limited to only a few known, adjustable parameters. Therefore, it is essential that the inter-relations between all externally controllable parameters and measurable process parameters are derived and made useful throughout the lifetime of a process and from process-to-process.